Evolution of multigene families by gene duplication and subsequent diversification is analyzed assuming a haploid model without interchromosomal crossing over. In this model, new genes are created by gene duplication. Compound poisson approximation and testing for gene. Such events can lead to duplications, deficiencies, and new linkage. Multigene families and the evolution of complexity. The birth and death evolution of multigene families. Higher organisms are complex, and their developmental processes are controlled by the sequential expression of genes that often form multigene families.
A significant portion of genes in the human genome belongs to multigene families, with each family containing several gene copies that have arisen via duplication, i. Multigene families that are known to be evolving under continued occurrence of unequal crossingover and gene conversion provide a different picture of evolution from that of the conventional population genetics. Evolution of multigene families 1 evolution of multigene families 2 orthologs homologs by speciation gene duplication and multigene families. In order to investigate the evolution of conotoxin multigene families among two closely related vermivorous. Groups of genes showing similarity with each other are referred to as a gene family, arising from wholesale or partial gene duplication. Organization and properties of antibody genes and other multigene families. The existence of multigene families is an important fact which needs to be considered when testing for gene cluster signi. A gene family may also be subdivided into subfamilies whenever convenient. The multigene family of rdna in drosophila reveals high levels of withinspecies homogeneity and betweenspecies diversity. Gene duplications are a major driving force of new function acquisition. A family of sequencerelated genes within a genome which evolved from a single ancestral gene by gene duplication and subsequent mutations. A multigene family is a group of genes that have descended from a common ancestral gene.
Shakhnovich be and koonin ev 2006 origins and impact of. View the article pdf and any associated supplements and figures for a period of 48 hours. This multigene family included seven families alpha, mu, pi, theta, sigma, zeta, and omega. Evolution by the birthanddeath process in multigene. It is wellaccepted that the multigene family mgf proteins. Ohta t 1991 multigene families and the evolution of complexity. Pdf the birthanddeath evolution of multigene families revisited. Deciphering highly similar multigene family transcripts. Evolution of substrate recognition across a multigene. In this study, reverse transcriptase pcr was employed to construct a transcriptional profile of mycoplasma pneumoniae lipoprotein genes contained in six multigene families. Wed like to understand how you use our websites in order to improve them. A cdna library has been constructed from an rna preparation highly enriched in silkmoth chorion mrnas. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue. Evolutionary history of the human multigene families.
Until around 1990, most multigene families were thought to be subject to concerted evolution, in which all member genes of a family evolve as a unit in concert. The evolution of multigene panel testing for hereditary cancers. Concerted and birthanddeath evolution of multigene families. Multigene families are susceptible to nonhomologous, or ectopic, recombination when homologous regions of different members of the. Moreover, immunoglobulins, tcell receptors, and, and mhc loci are part of a larger superfamily of genes, i.
Gene family a gene family is a set of several similar genes, formed by duplication of a single original. Human multigene families questions and study guide. Multigene family definition of multigene family by. Classification of multigene families of african swine. The complete sequence of the arabidopsis genome enables definitive characterization of multigene families and analysis of their phylogenetic relationships. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Many distinct clones have been identified from this library using a stepwise procedure. Multigene families whose member genes have the same function are generally believed to undergo concerted evolution that homogenizes the dna sequences of the member genes. Evolutionary history of human tetraparalogon hsa 12820. A gene family is a collection of several similar genes, formed by using. Evolution by the birthanddeath process in multigene families of the. Evolution of two major chorion multigene families as inferred from cloned cdna and protein sequences.
Multigene families that are known to be evolving under continued occurrence of unequal crossingover and gene. This lecture explains about the gene families and examples of gene families like alpha and beta globin gene families. Globin gene family can be considered as one such superfamily. Recently, it has been discovered that some genes exist in largescale repetitive structures, and that they are accompanied by newly described phenomena such as coincidental evolution. However, phylogenetic analysis of mhc and other immune system genes showed a quite different evolutionary pattern, and a new model called birthanddeath evolution was proposed. Multigene family article about multigene family by the. The mhc multigene family was originally thought to evolve under. Hence, phylogenetic trees are being derived from these multigene families. View enhanced pdf access article on wiley online library html view download pdf for offline viewing.
Genomic structure and evolution of multigene families. A gene family is a set of several similar genes, formed by duplication of a single original gene, and generally with similar biochemical functions. A circular view of human chromosomes shows the paralogons detected among human chromosomes 12820, including the. African swine fever virus asfv is a large and complex doublestranded dna virus that poses serious threats to the pig industry. The alpha and beta globins form two different multigene families within the same group. Evolution of the mammalian g protein alpha subunit. The two remarkable characteristics of multigene families as shown by hood and othersthe contraction and expansion of the gene number in a family and the coincidental. Use of a cdna library for studies on evolution and. Multigene medical definition merriamwebster medical. One such family are the genes for human hemoglobin.
Awellknownexampleofasupergene family is the globin superfamily that is composed of the. Evolution and variation of multigene families tomoko. Lipoprotein multigene families in mycoplasma pneumoniae. The birthanddeath model of multigene family evolution provides a framework to answer this question. Gene family a gene family is a set of several similar genes, formed by duplication of a single original gene, and generally with similar biochemical functions. Concerted and birthanddeath evolution of multigene. The evolution of multigene families has been the subject of. Multigene family is a group of genes that arose from a common ancestor by gene duplication. When ribosomal rna genes and other gene families in this class were first compared. The birth and death model of evolution over the last 2 decades, nei and colleagues conducted a number of key studies that provide the foundation for the theory that underlies the birth.
Evolutionary diversification of multigene families. Gene superfamiles are groups of two or more multigene families. It is now known that many multigene families exist in eukaryote genomes. Evolution of multigene families by gene duplication. A gene family is a set of homologous genes within one organism. Evolutionary history of the human multigene families reveals. Multigene families whose member genes have the same function are generally believed to undergo concerted evolution that homogenizes the dna sequences of. The prolamin genes of the triticeae can be grouped under three multigene families encoding the s. Multigene families are susceptible to nonhomologous, or ectopic, recombination when homologous regions of different members of the family misalign and genetic exchange takes place either intra or interchromosomally.
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